A medical device in the sense of the present application includes elongated catheters or electrode leads which can be inserted into a living body temporarily or permanently. Electrode leads are permanent implants which remain in, for example, the heart, brain, or spinal cord and are used to exchange therapeutic or diagnostic signals between an electromedical implant (e.g., implantable cardiac pacemaker, defibrillators, neurostimulators, cochlear implants, etc.) and an electrode surface at the opposite end of the electrode lead. A catheter is a small rigid or flexible tube that can be introduced into a body cavity to be treated. Such tubes are offered in various diameters. The body cavities, such as, for example, the bladder, stomach, intestine, vessels, etc., as well as the ear and heart, are probed, evacuated, filled, or rinsed with a catheter. This is done for diagnostic and/or therapeutic reasons.
All medical devices in the sense of the present application typically have the same or similar design. They have a proximal end and a distal end which points in the direction of the treatment site. Mounted on this distal end are devices relevant to therapy or diagnostics, such as, for example, electrodes for stimulating organs of the body or sensing body signals. The proximal end serves as an interface to an implant or external control, and therapy or diagnostic devices, and can also serve to enable control by a physician, such as, for example, controlling the flexible distal end using a control device. Situated between the proximal end and distal end of the medical device is an elongated body comprising at least one flexible or rigid tube. Such a tube is typically comprised of a continuous opening, which is also referred to as a lumen, and extends along the longitudinal axis of the tube. If the body is comprised of a plurality of tubes which extend in parallel and form a single unit, it is comprised of a plurality of lumina and is therefore referred to as a multi-lumina tube. Each of the lumina, in particular the outer lumina which are offset in the radial direction from the longitudinal axis, can form the continuous opening of the tube of a guide device.
Guide devices are generally used to guide cables or strips. The cables or strips in the guide devices can be used, in particular, to enable the distal end to be controlled, and/or to transmit therapeutic or diagnostic signals.
The catheters referred to as medical devices, in particular so-called ablation catheters which are used primarily in electrophysiology for the thermal destruction of a conduction path in the heart, typically comprise an aforementioned multi-lumina tube as catheter body, in the case of which several or all outer lumina can serve as lumina of a guide device. This means that a cable—in this case a control cable or control band—is guided in one lumen or each of the lumina. Each control cable extends through one of the lumina. Defined pulling motions on the cables are employed to redirect the catheter tip away from the longitudinal axis and thereby guide the catheter tip to the desired tissue region to be treated. For control, the physician typically uses a handle to operate the control cables or strips, which causes the cable to move relative to the lumen. Various electrode surfaces are located on the catheter tip, which are used to direct radio frequency signals into the tissue region for ablation.
A relative motion between a cable and lumen takes place even with electrode leads that remain in the body permanently; such electrode leads are also encompassed by the term “catheter” in the sense of the present application.
The body thereof, which is also referred to as an electrode body, basically has the same structure as the above-described catheter body and is generally equivalent thereto. In contrast, however, the electrode lead remains in the body permanently and is therefore exposed to other stresses. Likewise, such an electrode lead comprises control cables in the rarest cases, as well as electrically conductive supply cables or strips for transmitting electrical signals from the electromedical implant—on the proximal end of the electrode lead—to an electrode on the distal end of the electrode lead, or vice versa. These electrical supply cables likewise extend in the lumen of a tube. The electrode body can likewise be formed of a plurality of tubes in an interconnection, wherein the stranded conductors extend in one or more of the tubular lumina. The electrode lead is subjected to a continuous flexural load by, for example, the heart, which is in permanent motion, thereby resulting in relative motion between each tube in an electrode body and the stranded conductor.
In the following, the system comprised of a flexible tube (or rigid tube) having a continuous opening (lumen) and a cable extending therein (control cable or supply cable of an electrode lead) is referred to as the guide device. This means that, in a body of a medical device as an interconnection of a plurality of tubes, every tube in which a cable is routed is a guide device. The guide device forms the core of the medical device. This medical device can include even more devices for various applications, such as, for example, a balloon, connectors for measuring devices, a syringe for providing a fluid for treatment (e.g., a drug or another pharmaceutically active substance) or diagnosis (e.g., with contrast medium), or the like. Another lumen which temporarily accommodates a guide wire can also be present.
The guide device according to the subject of the present application can also be used in medical devices other than those stated, e.g., in minimally invasive instruments. In these devices, control is likewise performed using guide or puller cable(s) which move relative to a flexible tube or rigid tube.
In such a guide device, in which relative motion takes place between two different materials (usually, but not limited to, a polymer and/or plastic material on the side of the tube, and a metallic material on the side of the cable), a great deal of wear is typically observed. It is possible for a cable to become worn through by the surrounding tube material. In the control of catheters, in contrast, increased frictional force is observed, which encumbers control and makes therapy difficult or more time-consuming than expected.
A problem addressed by the present application is therefore that of creating a guide device or a medical device having greatly reduced wear or friction. A further problem is that of providing a simple and cost-effective method for manufacturing such a guide device or such a medical device.
The present application is directed toward overcoming one or more of the above-identified problems.